Occurrence of cyanobacteria in water used for food production: A review

Cyanobacteria have been part of the human diet for thousands of years. Environmental conditions such as high pH, light, temperature, and nutrients favour cyanobacterial growth which results in algal bloom formations. Cyanobacteria blooms may be toxic or non-toxic. Thus, the consumption of edible cyanobacteria such as spirulina may reduce the risks of cataracts and age-related muscular degeneration. Sulphate polysaccharides within some cyanobacteria have been shown to exhibit antitumor, anti-mutagenic, anti-inflammatory, antiviral activity against certain viruses and bacteria. There are many ways in which humans may be exposed to cyanobacteria and their cyanotoxins, with the most common route being eating and drinking of contaminated food and water, respectively. The current paper reviews cyanotoxin effects produced by cyanobacteria particularly in water and food, and its potential implications for human health. We further examine the quality of water used during food processing and developing a theoretical framework on cyanobacteria contamination of food. Concentrations of microcystin have been reported in crops and grain in Brazil, New Zealand and China. Microcystin concentrations of 8.31, 0.78 and 22 μg/kg were detected in lettuce, rape (Brassicas) and rice, respectively. Therefore, cyanotoxin transfers can occur through application of cyanobacteria contaminated water during food production.